Pedal attachment apparatus and method

ABSTRACT

A pedal assembly includes a mounting bracket, a pedal arm, and a pivot shaft pivotably connecting the pedal arm and the mounting bracket. The mounting bracket includes integrally formed bearing surfaces to support the pivot shaft and pedal arm. The pivot shaft is self-lubricating. The mounting bracket is a unitary component, with the bearing surfaces being inwardly-protruding surfaces formed through a deep drawing process. A treadle, or pedal pad, is attached to one end of the pedal arm. A magnetic assembly, including magnets and a ferromagnetic shield, is mounted to one end of the pivot shaft via features integrally formed with a mounting cap attached to the end of the pivot shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to provisional U.S. patent applicationentitled, “MODULAR PEDAL ASSEMBLY HAVING AN ELECTRONIC CONTROLLER,”filed Jan. 18, 2005, having a Ser. No. 60/644,884 and now pending, thedisclosure of which is hereby incorporated by reference in its entirety.This application also claims priority to provisional U.S. patentapplication entitled, “MODULAR PEDAL ASSEMBLY HAVING AN ELECTRONICCONTROLLER,” filed Jun. 24, 2005, having a Ser. No. 60/693,845 and nowpending, the disclosure of which is also hereby incorporated byreference in its entirety. This application further claims priority toprovisional U.S. patent application entitled, “ELECTRONIC CONTROLLER,”filed Jun. 2, 2005, having a Ser. No. 60/686,642 and now pending, thedisclosure of which is also hereby incorporated by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates generally to dynamic systems such as, forexample, pedal assemblies. More particularly, the present inventionrelates to electronic pedal assemblies and methods of operation thereof.

BACKGROUND OF THE INVENTION

Automobiles, motorcycles, boats and other types of vehicles typicallyinclude one or more pedals that control the speed at which the vehiclestravel and accelerate. For example, some vehicles include an acceleratorpedal, a brake pedal and a pedal that controls the clutch. Typically,each of these pedals is a complex mechanical system that includes aplurality of interconnected levers.

Many mechanical systems have a variety of shortcomings. For example,components in a mechanical system that are mechanically connected andmoveable relative to each other are subject to friction. As such, thesecomponents wear out over time. Also, fasteners connecting two or morecomponents in a mechanical system often loosen over time, typically as aresult of being subjected to extended periods of vibrations in thesystem. As such, the components of mechanical systems start to moverelative to each other in unintended directions (i.e., more and more“play” is introduced into the system).

In order to overcome some of the above-discussed shortcomings ofmechanical systems and, more particularly, the shortcomings ofmechanical pedals, electronic pedals have been developed. However, manycurrently-available electronic pedals suffer from a variety ofshortcomings as well. For example, some operators of the vehicles inwhich mechanical pedals have been replaced by electronic pedalsfrequently complain that the electronic pedals do not provide the samekind of operator feedback as mechanical pedals. In other words,electronic pedals do not have the same “feel” as the mechanical pedalsto which the operators have been accustomed to all of their lives. Also,some electronic pedals are subject to failing catastrophically andwithout warning if a single one of the electronic components includedtherein fails.

In addition to the above, both mechanical and electronic pedalstypically include a relatively large number of components (e.g., bolts,screws, rivets). Therefore, a substantial amount of time and effort istypically needed to assemble either a mechanical or electronic pedal.

At least in view of the above, it would be desirable to have provideelectronic pedals that overcome the shortcomings of mechanical pedalswhile retaining the “feel” of mechanical pedals. It would also bedesirable to provide electronic pedals that are relatively easy toassemble and that maintain the safety of a vehicular operator even ifthe pedal fails. Further, it would also be desirable to provide methodsfor operating and manufacturing such pedals.

SUMMARY OF THE INVENTION

The foregoing needs are met, to a great extent, by the presentinvention, wherein in one aspect an apparatus is provided that in someembodiments provides a simplified assembly for an electronic pedal.

In accordance with one embodiment of the present invention, a pedalassembly is provided. The pedal assembly includes a mounting bracket, apedal arm, and a pivot shaft. The pivot shaft pivotably connects thepedal arm and the mounting bracket. The mounting bracket includesintegrally formed bearing surfaces to support the pivot shaft, andthereby the pedal arm. The pivot shaft is self-lubricating, which may beaccomplished either by coating the pivot shaft with a self-lubricatingmaterial, or by fabricating it from a self-lubricating compositematerial. The mounting bracket is a unitary component, with the bearingsurfaces being inwardly-protruding surfaces formed through a deepdrawing process. A treadle, or pedal pad, is attached to one end of thepedal arm.

In accordance with another aspect of the present invention, a method ofmanufacturing a pedal assembly is provided. A mounting bracket havingintegrally formed bearing surfaces and a pedal arm are provided. Thepedal arm is pivotably attached to the mounting bracket via a pivotshaft, which sits directly adjacent the bearing surfaces.

In accordance with yet another embodiment of the present invention, apedal assembly generally includes means for converting translationalmotion into rotational motion, mounting means having integrated bearingmeans for supporting the motion converting means, and means forpivotably connecting the motion converting means and the mounting means.The motion converting means is a pedal arm that converts translationalmotion of a treadle attached at one end into rotation of the connectingmeans, which is a shaft. The mounting means is a unitary bracket thathas integrally formed, deep drawn bearing surfaces thereon.

In accordance with still another embodiment of the present invention, apivot shaft is provided. One end of the pivot shaft has affixed theretoa magnetic component mounting cap. On the magnetic component mountingcap are magnetic component locating features and magnetic componentretention features. Either or both features may be integrally formedwith the magnetic component mounting cap. These locating and retentionfeatures serve to locate and secure magnetic components—a shield andmagnets—to the end of the pivot shaft.

In yet a further aspect of the present invention, a method of mountingmagnetic components in a dynamic system is provided. A rotating shaft,having integrally formed magnetic component mounting features at one endthereof, is provided. One or more magnetic components, such as magnetsand a ferromagnetic shield, are placed with reference to the locatingfeatures, and secured via the retaining features, for example by heatstaking the retaining features, by overmolding the retaining features,or by riveting.

In still another embodiment, the present invention provides a pivotassembly including pivoting means and magnetic means. Magnetic componentmounting means are affixed to one end of the pivoting means in order tolocate and secure the magnetic means to the pivoting means. Thus, as thepivoting means rotates, the magnetic means rotate as well.

There has thus been outlined, rather broadly, certain embodiments of theinvention in order that the detailed description thereof herein may bebetter understood, and in order that the present contribution to the artmay be better appreciated. There are, of course, additional embodimentsof the invention that will be described below and which will form thesubject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of embodiments inaddition to those described and of being practiced and carried out invarious ways. Also, it is to be understood that the phraseology andterminology employed herein, as well as the abstract, are for thepurpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conceptionupon which this disclosure is based may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a pedal assembly according to anembodiment of the invention.

FIG. 2 is a perspective view of a pivot shaft and mounting cap accordingto an embodiment of the invention.

FIG. 3 is an exploded view of the hysteresis assembly illustrated inFIG. 1

FIG. 4 illustrates the shaft and elastic member support illustrated inFIG. 3.

FIG. 5 illustrates an exploded view of the hysteresis blocks illustratedin FIG. 3.

FIG. 6 is a cross-sectional view of the sensor assembly illustrated inFIG. 1.

FIG. 7 is a blown-up perspective view of the sensor assembly illustratedin FIGS. 1 and 6.

FIG. 8 is a side view of a pedal assembly according to anotherembodiment of the present invention wherein a kickdown mechanism isincluded.

FIG. 9 is an exploded view of the kickdown mechanism illustrated in FIG.8.

FIG. 10 is a side view of the pedal assembly illustrated in FIG. 8wherein the kickdown mechanism is engaged with the triggering mechanism.

FIGS. 11-13 illustrates graphs of the amount of force needed to causethe treadle in the pedal assembly illustrated in FIG. 8 to movespecified distances when three different kickdown mechanisms areattached thereto.

FIG. 14 is a perspective view of a bottom surface of a treadle accordingto an embodiment of the present invention.

FIG. 15 is a perspective view of the treadle illustrated in FIG. 14wherein the treadle is attached to an end of a pedal arm according to anembodiment of the present invention.

DETAILED DESCRIPTION

Embodiments in accordance with the present invention will now bedescribed with reference to the drawing figures, in which like referencenumerals refer to like parts throughout. FIG. 1 is an exploded view of apedal assembly 10 according to an embodiment of the invention. The pedalassembly 10 generally includes a mounting bracket 12, a pedal arm 14, arotor assembly 16, a sensor assembly 18, a hysteresis assembly 20, and atreadle 22 attached to one end of pedal arm 14. Pedal arm 14 may beunitary or multi-piece, and converts translation of treadle 22 intorotation of rotor assembly 16, which rotation is in turn sensed bysensor assembly 18. Hysteresis assembly 20 provides friction and areturn force to pedal assembly 10. The components and operation ofsensor assembly 18 and hysteresis assembly 20 are described in furtherdetail below.

Rotor assembly 16 includes a shaft 24, an end cap 26, and magneticassembly 28. Magnetic assembly 28, in turn, includes a shield 30 andmagnets 32. A mounting cap 34, to which magnetic assembly 28 isattached, is provided on at least one end of shaft 24 adjacent sensorassembly 18. In certain embodiments, mounting caps 34 and magneticassemblies 28 are provided at both ends of shaft 24 adjacentcorresponding sensor assemblies 18. Shaft 24 and end cap 26 are securedtogether, for example by an appropriate fastener 36, such as a bolt, ascrew, or a pin.

Shaft 24 connects pedal arm 14 and mounting bracket 12. Shaft 24 isself-lubricating, such as a Teflon®-coated shaft or a composite Delrin®(Delrin® 500CL) shaft. The use of a self-lubricating shaft 24substantially eliminates the need for discrete bearings supporting pedalarm 14. That is, shaft 24 functions in place of a bearing, permittingsimpler assembly of pedal assembly 10 and, in some embodiments, up toapproximately fifteen million actuation cycles of pedal assembly 10without failure.

Mounting bracket 12 includes integrally-formed, inwardly-protrudingbearing surfaces 38 to support pivot shaft 24 and pedal arm 14. Mountingbracket 12 is a single component formed from a rigid material, forexample steel, by an appropriate machining process, for examplestamping. Bearing surfaces 38 are deep drawn into mounting bracket 12.First, small holes are created on mounting bracket 12 at the desiredlocations of bearing surfaces 38. Mounting bracket 12 is then drawn atthese holes to the required depth and diameter for bearing surfaces 38via a series of successive punches or a cone-shaped forming die.

Mounting bracket 12, pedal arm 14, and rotor assembly 16 are assembledby aligning apertures 40 in pedal arm 14 with bearing surfaces 38 onmounting bracket 12. Shaft 24 is then inserted so as to pivotallyconnect pedal arm 14 and mounting bracket 12. The interior profile ofapertures 40 complements the exterior profile of shaft 24, therebyensuring a proper, secure fit between these components and conversion oftranslation of treadle 22 into rotation of rotor assembly 16. That is,pedal arm 14 does not rotate freely about shaft 24; rather, pedal arm 14and shaft 24 rotate together upon bearing surfaces 38. Once shaft 24 ispositioned, end cap 26 is secured thereto in order to hold shaft 24 inplace.

As described above, magnetic assembly 28 (shield 30 and magnets 32) isattached to shaft 24 at one end thereof on mounting cap 34. Mounting cap34 is attached to shaft 24 so as to rotate with shaft 24 when treadle 22is depressed or released. In certain embodiments of the presentinvention, mounting cap 34 is integrally formed with shaft 24, though itis regarded as within the scope of the present invention to fixedlyattach a separate mounting cap 34 to shaft 24.

FIG. 2 is a perspective view of a pivot shaft 24 and mounting cap 34according to an embodiment of the invention. As shown in FIG. 2,mounting means 42 for magnetic assembly 28 are integrally formed onmounting cap 34, for example by molding mounting means 42 thereon.Mounting means 42 generally include shield locating features, such astowers 44, magnet locating features, such as slots 46, and retentionfeatures, such as pins 48. In certain embodiments of the presentinvention, a pair of shield locating towers 44 project from mounting cap34, and shield 30 fits around towers 44, as shown in FIG. 1. That is,the exterior profile of towers 44 corresponds to the interior profile ofshield 30. Similarly, a pair of magnet locating slots is provided intowhich magnets 32 are fit.

Once installed with reference to locating features 44, 46, shield 30 andmagnets 32 are secured on mounting cap 32. In certain embodiments of thepresent invention, shield 30 and magnets 32 are secured via rivetsdriven into the retention features. In other embodiments, pins 48 areheat-staked to secure shield 30 and magnets 32. In still otherembodiments, shield 30 and magnets 32 are secured through an overmoldingprocess applied to mounting means 42. In substantially all embodiments,however, the end result is a simplified unitary mounting for therotating magnetic assembly 28. Thus, as treadle 22 is depressed orreleased, pedal arm 14 will convert this translation into rotation ofshaft 24, mounting cap 34, and magnetic assembly 28, which rotation isdetected by sensor assembly 18 as further described below.

Referring now to FIGS. 1 and 3, hysteresis assembly 20 provideshysteresis forces, including frictional forces and return forces, topedal assembly 10. Specifically, hysteresis assembly 20 provides abaseline force, herein referred to as an “initial displacement force”necessary to displace pedal arm 14 from its initial (i.e., idle)position. Hysteresis assembly 20 also provides frictional forcesdesigned to give a user the impression of a mechanical pedal assembly10, and a return force intended both to give the impression of amechanical pedal and to bias pedal arm 14 towards its initial position.Thus, if the user releases treadle 22, pedal arm 14 will return to itsinitial, idle position, and will not stick in an open position.

FIG. 3 is an exploded view of the hysteresis assembly 20 illustrated inFIG. 1. Hysteresis assembly 20 generally includes an elastic membersupport 50, a first hysteresis block 52, a second hysteresis block 54,and an elastic member, for example springs 56, though other elasticmembers are regarded as within the scope of the invention. Springs 56connect elastic member support 50 and first hysteresis block 52 viaseats 58 thereon. An alignment pin 60, which, in certain embodiments ofthe present invention, is integrally formed with elastic member support50, aligns elastic member support 50 and second hysteresis block 54.That is, alignment pin 60 maintains the relative orientation of elasticmember support 50 and hysteresis blocks 52, 54, as well as springs 56,such as by slidably engaging a collar 62 on second hysteresis block 54.Hysteresis assembly 20 also includes a shaft 64 to connect hysteresisassembly 20 to mounting bracket 12, and a pin 66 to attach hysteresisassembly 20 to pedal arm 14, both shown in FIG. 1. In some embodimentsin accordance with the invention, pin 66 includes ears 68. Whenhysteresis assembly 20 is installed in pedal assembly 10, ears 68 arepositioned between mounting bracket 12 and pedal arm 14 to preventlateral movement of pedal arm 14 within mounting bracket 12. Similarly,shaft 60 may include rings 70 to retain shaft 60 within mounting bracket12 and to prevent sliding between shaft 60 and elastic member support50, which has a corresponding ridge 72 thereon, as illustrated in FIG.4, which illustrates the shaft 60 and elastic member support 50illustrated in FIG. 3.

Returning to FIG. 1, shaft 64 pivotally attaches hysteresis assembly 20to mounting bracket 12 at mounting holes 74, with outermost rings 70abutting the interior face of mounting bracket 12. As one of skill inthe art will appreciate from this disclosure, hysteresis assembly 20 isinstalled underneath pedal arm 14, between sidewalls 76 of mountingbracket 12, such that displacement of pedal arm 14 also causesdisplacement of hysteresis assembly 20, with hysteresis blocks 52, 54disposed between sidewalls 76. However, while pedal arm 14 pivots aboutshaft 24, hysteresis assembly 20 pivots about shaft 64. Therefore, aspedal arm 14 pivots, the distance between pin 66 and shaft 24 changes,displacing springs 56.

Springs 56 are biased to return pedal arm 14 to its initial, idleposition. As pedal arm 14 is displaced, via pressure applied to treadle22, springs 56 are stretched from equilibrium, generating a return forceF_(r). The return force will tend to restore springs 56 to theiroriginal length, which, in turn, will tend to urge pedal arm 14 back toits initial, idle position. For linear springs 56, F_(r) is a functionof the displacement from equilibrium (x) given by the equation F_(r)=kx,where k is the spring rate. It is thus possible to customize the returnforce profile of hysteresis assembly 20, given a particular geometry ofpedal assembly 10, by selecting springs 56 to have a spring rate kcorresponding to the desired return force profile.

As with the selection of springs 56, the location of mounting holes 74on mounting bracket 12 is determined through an analysis of desiredhysteresis characteristics. First, a desired initial displacement forceis selected. (As specified above, the “initial displacement force” isthat force necessary to displace pedal arm 14 from its initial, idleposition. This force may also be referred to as the “idle force.”) Aswith the return force F_(r), the initial displacement force is relatedto the spring rate k. Thus, if hysteresis assembly 20 is installed intopedal assembly 10 with springs 56 near equilibrium, only a very smallforce will be required to initially displace pedal arm 14 from idle. Onthe other hand, if hysteresis assembly 20 is installed into pedalassembly 10 with springs 56 displaced from equilibrium, a proportionallylarger force will be necessary to initially displace pedal arm 14. Itshould be recognized that changing the position of mounting holes 74will change the initial idle position length of springs 56, andtherefore the idle force. Depending upon the spring rate k of springs56, it is possible to vary the initial displacement force byapproximately 25% by moving mounting holes 74 approximately 2 mm. Oncethe desired initial displacement force has been identified, thecorresponding location of mounting holes 74 may be calculated.

As shown in FIGS. 1, 3, and 5, a first surface 78 on first hysteresisblock 52 and a second surface 80 on second hysteresis block 54 interfaceat a slope α. When pedal arm 14 is displaced, a component of thereaction force to springs 56 acts to slide hysteresis blocks 52, 54relative to each other along the sloped interface. In turn, thisrelative sliding motion causes at least one of frictional surfaces 82,84 to frictionally engage the interior surface of sidewalls 76 onmounting bracket 12. Additional pressure on treadle 22 forces hysteresisblocks 52, 54 further apart, increasing the normal force betweenfrictional surfaces 82, 84 and sidewalls 76, and thus the frictionalforce acting to inhibit further depression of pedal arm 14. The angle ofthe slope α between first and second surfaces 78, 80 is calculated toprovide a desired frictional force profile as pedal arm 14 is displacedfrom its initial, idle position. Likewise, the coefficient of frictionbetween hysteresis blocks 52, 54 along first and second surfaces 78, 80and the coefficient of friction between frictional surfaces 82, 84 andsidewalls 76 may be adjusted to achieve the desired frictional forceprofile. Further, it is possible to configure hysteresis blocks 52, 54to supply a component of the initial displacement force simply by havingfrictional surfaces 82, 84 in frictional engagement with sidewalls 76when pedal arm 14 is in its initial, idle position.

As should be clear from the foregoing, the frictional forces betweenhysteresis blocks 52, 54 and sidewalls 76 are directly related to theforces generated by springs 56. That is, increased spring forces causeincreased frictional forces and vice versa. This ensures that pedalassembly 10 complies with industry standards requiring return-to-idlewhen treadle 22 is released. Further, in the unlikely event a spring 56fails, the return force F_(r) would be halved, but so too would thefrictional forces. Where frictional forces are independent of springforces, it is possible for pedal arm 14 to “stick” in an open positionwhen there is such a failure, as the return force may be insufficient toovercome the frictional force where the two are unrelated.

A pedal assembly 10 with customized hysteresis forces can be constructedusing the principles elucidated above. For example, it is possible toalter the idle and Wide Open Throttle (WOT) pedal forces whilemaintaining the same relative relationship between the two.Alternatively, either force may be kept constant, and the differencebetween the two varied. First, the end user identifies the desiredinitial displacement force, the desired return force profile, and thedesired frictional fore profile. Analyses are then conducted todetermine the spring rate k of an elastic member 56 corresponding to thedesired return force profile, the slope α of the interface betweenhysteresis blocks 52, 54 corresponding to the desired frictional forceprofile, and the location of mounting holes 74 corresponding to thedesired initial displacement force. If desired, the frictional forceprofile may also be adjusted by selecting appropriate coefficients offriction as described above. Hysteresis assembly 20 is then constructedusing an elastic member 56 with spring rate k and a pair of adjacenthysteresis blocks 52, 54 interfacing at the calculated slope α.Appropriately located mounting holes 74 are made on mounting bracket 12,and an end of hysteresis assembly 20 is attached via shaft 64.

As will be appreciated by one of skill in the art, FIG. 1 illustrates adynamic system in the form of pedal assembly 10. However, other dynamicsystems are also within the scope of the present invention. For example,systems wherein it is desired to monitor the position of a movingcomponent and/or wherein it is desired to provide a hysteresis force tothe moving component are also within the scope of the present invention.

The pedal assembly 10 illustrated in FIG. 1 includes a movable componentin the form of treadle 22. As previously discussed and illustrated inFIG. 1, treadle 22 is connected to pedal mounting bracket 12 via pedalarm 14.

Also illustrated in FIG. 1 is end cap 26 that is connected to a rotorshaft 24 using fastener 36 in order to form rotor assembly 16. Asfurther illustrated in FIG. 1 and previously discussed above, rotorassembly 16 is connected to treadle 22 via pedal arm 14 and rotorassembly 16 is configured to rotate when treadle 22 moves between afirst position (e.g., an idle position) and a second position (e.g., anopen throttle position).

FIG. 1 also illustrates a pair of magnets 32 that each have anassociated emitted magnetic field that, although not illustrated in FIG.1, emanates from each magnet 32 and grows gradually weaker at greaterdistances away from each magnet 32. Each magnet 32, according to certainembodiments of the present invention, is fixedly connected to rotorassembly 16 via the slots 46 and pins 48 illustrated in FIG. 2 thatprotrude from a proximate end of shaft 24.

Positioned adjacent to rotor assembly 16, also on the proximate endthereof, is sensor assembly 18. Sensor assembly 18, as illustrated inFIG. 1, is attached to mounting bracket 12 via the use of the twofasteners 86 illustrated on the right-hand side of FIG. 1. As will bediscussed below, sensor assembly 18 is configured to detect the positionof one or both of the magnets 32 as they rotate about the longitudinalaxis of rotor shaft 24 when treadle 22 is depressed by a user of thepedal assembly 10. Typically, sensor assembly 18 detects the position ofthe magnets 32 using a Hall sensor, as will also be described below.

As mentioned above, FIG. 1 also illustrates a magnetic shield 30 that ispositioned adjacent to the towers 44 protruding from mounting cap 34 onrotor shaft 24 of rotor assembly 16. When all of the components of rotorassembly 16 illustrated in FIG. 1 are connected to each other, magneticshield 30 substantially surrounds a portion of rotor assembly 16 that isadjacent to each of the magnets 32. As will be discussed below, magneticshield 30 not only prevents exterior magnetic fluxes from interactingwith either of the magnets 32, but also acts as a flux concentrator thatconcentrates the magnetic fluxes from each of the magnets 32 within theinterior of the magnetic shield 30.

FIG. 6 is a cross-sectional view of the sensor assembly 18 illustratedin FIG. 1. As illustrated in FIG. 6, a plurality of cavities 88 areincluded with sensor assembly 18 and are configured to accommodate theinsertion of one or more protrusions (e.g., slots 46 and/or pins 48)from mounting cap 34, the magnets 32 connected thereto, and the magneticshield 30 substantially surrounding magnets 32. According to certainembodiments of the present invention, a Hall sensor is included insensor assembly 18 as part of a printed circuit board 90 that extendsbetween the cavities 88 in sensor assembly 18.

In certain embodiments of the present invention, a second Hall sensor isincluded on printed circuit board 90. According to some of theseembodiments, the second Hall sensor is substantially identical to,electrically isolated from and slightly offset from the above-discussedfirst Hall sensor. The use of two such Hall sensors positioned asdescribed above can compensate for the fact that, in some embodiments ofthe present invention, a Hall sensor cannot be placed at the exactcenter of rotation of rotor assembly 16 due to way that the Hall sensoris packaged onto printed circuit board 90.

As illustrated in FIG. 6, first printed circuit board 90 is connected toa circuit board 92 that extends vertically within a casing 94. In turn,circuit board 92 is connected to a set of wires 96 that extend outsideof casing 94 and that, according to certain embodiments of the presentinvention, are connected to a microprocessor or controller (not shown).

As will be discussed in greater detail below, according to certainembodiments of the present invention, one or more of the components insensor assembly 18 are programmable. As such, the format or protocol ofan output signal that travels through wires 96 and out of sensorassembly 18 may be switched without having to physically reconfigure anyof the components in sensor assembly 18.

According to certain embodiments of the present invention, sensorassembly 18 meets or exceeds Ingress Protection 67 (IP67) standards. Inother words, according to certain embodiments of the present invention,casing 94 is configured such that overall sensor assembly 18 issubstantially water-tight and prevents dust from interfering with theelectronics of sensor assembly 18.

FIG. 7 is an exploded perspective view of the sensor assembly 18illustrated in FIGS. 1 and 6. In FIG. 7, circuit board 92 is illustratedas being enclosed between casing 94 and a casing cover 98. Also,enclosed between casing 94 and cover 98 is an additional magnetic shield100. Additional magnetic shield 100 supplements previously-discussedmagnetic shield 30 in that it prevents exterior magnetic fluxes parallelto the longitudinal axis 45 (see FIG. 1) of shaft 24 from enteringsensor assembly 18, whereas magnetic shield 30 (see FIG. 1) protects thevolume that it surrounds mainly from exterior magnetic fluxes parallelto the longitudinal axis of shaft 24. Therefore, in conjunction withmagnetic shield 30 illustrated in FIG. 1, additional magnetic shield 100illustrated in FIG. 7 protects magnets 32 and Hall sensors positionedbetween the magnets 32 from exterior magnetic fluxes both in the axialand radial directions relative to rotor assembly 16.

Although additional magnetic shield 100 is illustrated in FIG. 7 asconforming to the dimensions of the interior perimeter of casing 94,according to other embodiments of the present invention, additionalmagnetic shield 100 takes on alternate geometries. For example, whensimplicity and cost-reduction are favored, a commonly-available circularmetallic washer may be used as additional magnetic shield 100.

According to another embodiment of the present invention, a method ofmonitoring a dynamic system such as, for example, the above-discussedpedal assembly 10, is provided. According to this method, a componentsuch as, for example, treadle 22, is moved between a first position(e.g., an idle position where the vehicle that includes pedal assembly10 is at rest) and a second position (e.g., an open throttle positionwhere the vehicle is being accelerated). Also according to this method,a rotor such as, for example, rotor assembly 16, is rotated as thecomponent moves between the first position and the second position.Typically, this rotating step also includes rotating an emitter (e.g.,one of magnet 32, which emits a magnetic field) that is fixedlyconnected to the rotor.

As the rotor and fixedly connected emitter are each rotated, theposition of the first emitter is monitored with a sensor that ispositioned adjacent to the rotor (e.g., one of the above-discussed Hallsensors on printed circuit board 90). Since the Hall sensors on printedcircuit board 90 are physically separated from magnets 32, and sincemagnets 32 are fixedly linked to treadle 22 through pedal arm 14 androtor assembly 16, this monitoring step provides a non-contact (i.e.,frictionless) method of monitoring the position of treadle 22.

According to certain embodiments of the present invention, the abovemethod allows for the programming of the first sensor to output aparticular type of signal. For example, one or both of theabove-discussed Hall sensors may be programmed to output a continuousanalog or a discrete digital signal. As discussed above, suchprogrammability allows for changes to be made to the dynamic systemwithout having to physically alter any of the components includedtherein.

In embodiments of the present invention that include a second sensor,the above method includes monitoring the position of the first emitterwith the second sensor, which is typically positioned adjacent to therotor. According to these embodiments, the first signal from the firstsensor is processed (e.g., averaged) along with a second signal from thesecond sensor to determine the position of the first emitter. Asdiscussed above, the use of two sensors is particularly useful inembodiments of the present invention where the packaging of a Hallsensor prevents the Hall sensor from being positioned directly in thecenter of the rotor.

One of the advantages of certain embodiments of the present invention isthat, particularly when the sensors included in the dynamic systemdiscussed above are Hall sensors, the entire system may be calibratedsimply by taking a reading from sensor assembly 18 at a first positionof treadle 12 (e.g., at idle) and at a second position of treadle 12(e.g., at Wide Open Throttle (WOT)). Such convenient and rapidcalibration is possible in dynamic systems according to certainembodiments of the present invention because the electronic sensors usedtherein (e.g., Hall sensors) react substantially linearly in response tochanges in the position of the emitters that they monitor. In contrast,mechanical pedals do not necessarily react linearly and tend to “loosen”over time as the components thereof wear against each other. Thus, insome mechanical pedals, complex, time-consuming calibration proceduresare typically performed on a regular basis.

Another disadvantage of some mechanical pedals is that, as they wear,the range of the signal values that is emitted therefrom upon depressionor release of the treadle by a user varies. For example, if a user movesa treadle from an idle position to a WOT position, an analog signal sentfrom the pedal assembly to a controller in the vehicle may not alwaysstay within the same range due to linkages of the included components.For example, the treadle at idle may not always return to the samesignal level.

In order to address this shortcoming of mechanical pedals, certainelectronic pedal assemblies according to some embodiments of the presentinvention restrict the sensors included therein to emitting an outputsignal having a value between a first threshold value and a secondthreshold value. Any circuitry that becomes apparent to one of skill inthe art upon practicing the present invention may be used in order toimplemented such restrictions.

FIG. 8 is a side view of a pedal assembly 102 according to anotherembodiment of the present invention. Like the pedal assembly 10illustrated in FIG. 1, pedal assembly 102 includes a treadle 22 that isconnected to a mounting bracket 12 via a pedal arm 14. During operationof pedal assembly 102, pedal arm 14 rotates relative to bearing surfaces38 on mounting bracket 12 (see FIG. 1).

Unlike the pedal assembly 10 illustrated in FIG. 1, pedal assembly 102includes a resistance mechanism, referred to herein as a kickdownmechanism 104, that is attached to pedal arm 14 of pedal assembly 102.Below kickdown mechanism 104 is located a triggering mechanism 106 that,in the embodiment of the present invention illustrated in FIG. 8, takesthe form of a flat plate attached to mounting bracket 12. However,alternate geometries for triggering mechanism 106 are also within thescope of the present invention.

FIG. 9 is an exploded view of kickdown mechanism 104 illustrated in FIG.8. As illustrated in FIG. 9, kickdown mechanism 104 includes a casing108 configured to be attached to a pedal assembly. In FIG. 8, casing 108of kickdown mechanism 104 is attached to pedal arm 14 of pedal assembly10 between treadle 22 and bearing surface 33.

Inside casing 108 is a fixed magnetic component 110. The proximate anddistal ends of fixed magnetic component 110 slide into slots 112 locatedin a lower portion of casing 108. As such, once fixed magnetic component110 is inserted into casing 108, it is no longer free to move.

Also inside casing 108 is a moveable magnetic component 114. The lengthof moveable magnetic component 114 is typically slightly less than thedistance between the two interior sidewalls 116 of casing 108.Therefore, moveable magnetic component 114 is configured to slide up anddown within casing 108.

Positioned adjacent to moveable magnetic component 114 is a contactmechanism 118 that, in FIG. 9, takes the form of a plunger. As will bediscussed below with reference to FIG. 10, contact mechanism 118 isconfigured to contact triggering mechanism 106 when treadle 22 in pedalassembly 10 is depressed beyond a predetermined position.

When all of the components in FIG. 9 are assembled, contact mechanism118 extends through a hole 120 in fixed magnetic component 110. However,according to other embodiments of the present invention, contactmechanism 118 does not travel through any portion of fixed magneticcomponent 110. For example, a portion of contact mechanism 118 maytravel next to fixed magnetic component 110.

Also illustrated in FIG. 9 is an elastic member 122 that issubstantially enclosed within casing 108, particularly when cover 124 isattached to casing 108. Elastic member 122, which is illustrated in FIG.9 as a spring, is positioned between moveable magnetic component 114 andan upper interior side wall 126 of casing 108 when all of the componentsof kickdown mechanism 104 are assembled together. According to certainembodiments of the present invention, one or both of the ends of elasticmember 122 are physically connected to casing 108 and/or moveablemagnetic component 114. However, according to other embodiments, theelastic member 122 is held in compression between moveable magneticcomponent 114 and upper interior side wall 126 and/or is confined by theinterior sidewalls 116 and therefore remains unattached at either end.

According to another embodiment of the present invention, a method ofaltering a force needed to depress a pedal component (e.g., a treadle)as the pedal component travels along a path is provided. An example ofthis method will be described with reference to FIG. 8, wherein kickdownmechanism 104 is offset from triggering mechanism 106, and FIG. 10,which is a side view of pedal assembly 102 wherein kickdown mechanism104 is engaged with triggering mechanism 106. In the discussion below,the pedal component is treadle 22 and the path is the one along whichtreadle 22 travels as kickdown mechanism 104 travels between theun-engaged position relative to triggering mechanism 106 illustrated inFIG. 8 and the engaged position illustrated in FIG. 10.

The above-mentioned method includes providing a first resistancecomponent to a pedal component as the pedal component travels along afirst portion of a path. When implemented using pedal assembly 102, thisstep includes providing a first level of resistance to a user's foot asthe user depresses treadle 22 from the position illustrated in FIG. 8 toa position where contact mechanism 118 just comes into contact withtriggering mechanism 106. This first level of resistance may beprovided, for example, using hysteresis assembly 20 in the mannerdiscussed above with reference to pedal assembly 10.

It should be noted that the above-discussed kickdown mechanism has avariety of uses. For example, the higher level of force needed todepress the treadle further can be used to alert operators of vehiclesthat they may be operating the vehicle unsafely. In other words, akickdown mechanism may be used to alert drivers of automobiles that theyare speeding. As another example, kickdown mechanisms may be used tooptimize fuel efficiency of a vehicle. More specifically, the forceexerted by the kickdown mechanism can be use to alert a user that thevehicle is being operated outside of the most fuel-efficient range ofparameters.

The method also includes supplementing the first resistance componentwith a second resistance component as the pedal component travels alonga second portion of the path. When implementing this step using pedalassembly 102, contact mechanism 118, fixed magnetic component 110 (whichis located inside of casing 108 shown in FIG. 8) and moveable magneticcomponent 114 (which is also located inside of casing 108) are used.More specifically, as treadle 22 keeps moving toward the positionillustrated in FIG. 10 after contact mechanism 118 initially comes intocontact with triggering mechanism 106, contact mechanism 118 will beginapplying force to moveable magnetic component 114. In turn, sincemoveable magnetic component 114 is magnetically attracted to fixedmagnetic component 110 moveable magnetic component 114 will resist beingmoved. As a result, the attractive magnetic force between moveablemagnetic component 114 and fixed magnetic component 110 will provide asecond resistance component of force that will have to be overcome asthe motion of treadle 22 continues.

It should be noted that, as contact mechanism 118 (illustrated in FIG.9) is driven to positions that initially force magnetic components 110and 114 to lose direct contact with each other and that subsequentlymove magnetic components 110 and 114 further away from each other, theattractive magnetic force between the components diminishes. As such,certain embodiments of the above-discussed method include initiallyincreasing and subsequently decreasing the second resistance componentas the pedal component travels along the second portion of the path.

In addition to the above-discussed steps, the method also includesfurther supplementing the first resistance component and the secondresistance component with a third resistance component as the pedalcomponent travels along a third portion of the path. When implementingthis further supplementing step using pedal assembly 102, elastic member122 (i.e., a spring) is used to provide the third resistance component.In other words, as treadle 22 continues to move and continues to forcemore and more of contact mechanism 118 into casing 108, magneticcomponent 114 will compress elastic member 122 more and more. As aresult, elastic member 122 will exert more and more mechanical springforce to resist motion of magnetic component 114 and, in turn, contactmechanism 118 and treadle 22.

According to certain embodiments of the present invention (see FIG. 9),magnetic components 110 and 114 are not included in kickdown mechanism104. In such embodiments, a mechanical force (from elastic member 122)provides the above-discussed second resistance component. FIGS. 11-13each illustrate a graph of the amount of force (F) needed to causetreadle 22 in pedal assembly 102 to move specified distances (s) whenthree different kickdown mechanisms are attached thereto. In FIG. 11,only magnetic components 110 and 114 are included within casing 108. Theamount of force needed to move treadle 22 increases sharply when themovement of contact mechanism 118 is initially impeded by the magneticcomponents 110 and 114. However, once the magnetic components 110 and114 separate and move farther and farther apart, their influence oncontact mechanism 118 diminishes.

The graph in FIG. 12 is generated using a kickdown mechanism thatincludes only elastic member 122. In such embodiments of the presentinvention, as the contact mechanism 118 continues to compress elasticmember 122, more and more force is needed to move treadle 22 further.

The graph in FIG. 13 is generated using magnetic components 110 and 114and elastic member 122. At a first point along the x-axis (i.e., at adistance equal to s₁), a position is reached where the magneticcomponent of resistive force produced by magnetic components 110 and 114has to be overcome for treadle 22 to continue moving. Then, at a secondpoint along the x-axis (i.e., at a distance equal to s₂), the mechanicalcomponent of resistive force has to be overcome for treadle 22 tocontinue moving.

FIG. 14 is a perspective view of a bottom surface of a treadle 128according to an embodiment of the present invention. FIG. 15 is aperspective view of treadle 128 wherein treadle 128 is attached to anend of a pedal arm 130 according to an embodiment of the presentinvention. As illustrated in FIG. 14, treadle 128 includes four flexibleprotrusions 132 and, as illustrated in FIG. 15, pedal arm 130 includes aplurality of engaging surfaces 134 configured to accommodate engagementof flexible protrusions 132 therewith.

According to certain embodiments of the present invention, protrusions132 are each polymeric and each include a tab 133 at or near the freeend thereof. According to some of these embodiments, the engagingsurfaces 134 include holes, slots, depressions or other surface featuresinto which tabs 133 may be inserted in order to secure treadle 128 topedal arm 130.

Once treadle 128 has been secured onto pedal arm 130, protrusions 132according to certain embodiments of the present invention are configuredto incur plastic deformation upon detachment of treadle 128 from pedalarm 130. According to other embodiments of the present invention,protrusions 132 are configured to fracture upon detachment of treadle128 from pedal arm 130. Either way, once treadle 128 has been detached,it cannot be reattached to pedal arm 130. Thus, a disincentive isprovided to using potentially unsafe refurbished treadles instead ofreplacing a damaged treadle with a new one.

Both sets of engaging surfaces 134 illustrated in FIG. 15 are positionedsubstantially opposite each other. Also, both sets of protrusions 132are positioned substantially parallel to each other. However, even asingle protrusion and engaging surface combination may be used to securea treadle to a pedal arm, and more than the four such combinationsillustrated in FIG. 15 may be used. Also, the positioning of protrusions132 relative to each other and of engaging surfaces 134 relative to eachother will depend upon the geometries of the components in the pedalsystem that includes the treadle.

According to another embodiment of the present invention, a method ofassembling a pedal is provided. The method typically includeselastically deflecting a first protrusion of a treadle a first amount.When implementing this step using treadle 128, one of the protrusions132 may be deflected a small amount that will neither cause plasticallydeformation nor fracture thereof. For example, a protrusion 132 may bepressed against the edge of an engaging surface 134 on pedal arm 130until the protrusion 132 deflects just enough to allow the tab 133thereon to slide relative to the engaging surface 134.

The method also includes positioning the first protrusion adjacent to afirst engaging surface on a pedal arm that is pivotally connected to abracket. When implementing this step using treadle 128, theabove-discussed tab 133 is slid relative to the engaging surface 134until the tab 133 is aligned with a hole, slot or depression on theengaging surface 134.

Pursuant to the positioning step, the method includes engaging the firstengaging surface with the first protrusion by reducing the first amountof deflection in the first protrusion. Again, when implementing thisstep using treadle 128, after deflecting the above-discussed protrusion132 and aligning the tab 133 with the hole, slot or depression on theengaging surface 134, the tab 133 enters (i.e., engages with) the hole,slot or depression and the protrusion 132 returns to its undeflectedshape.

According to certain embodiments of the present application, the methodalso includes elastically deflecting a second protrusion of the treadlea second amount, positioning the second protrusion adjacent to a secondengaging surface on the pedal arm, wherein the second engaging surfaceis substantially parallel to the first engaging surface, and engagingthe second engaging surface with the second protrusion by reducing thesecond amount of deflection in the second protrusion. Each of thesesteps relative to the second protrusion may be performed in a manneranalogous to the corresponding steps relative to the first protrusionand, as will be appreciated by one of skill in the art upon practicingthe present invention, the use of multiple protrusions and engagingsurfaces more securely attaches the treadle to the pedal arm.

When, pursuant to attaching a treadle to a pedal arm, it is desired toremove the treadle, the above-discussed method also includes eitherplastically deforming the first protrusion upon disengagement of thefirst protrusion and the first engaging surface or fracturing the firstprotrusion upon disengagement of the first protrusion and the firstengaging surface. Either way, the above-discussed used of potentiallyunsafe refurbished treadles is substantially prevented.

In order to implement either of these plastically deforming orfracturing steps, a number of methods may be used. For example, theabove-discussed tabs 133 may be configured to engage with theabove-discussed engaging surfaces 134 in such a manner no convenientmethod or tooling exists for extricating the tabs 133 from the engagingsurfaces 134.

The many features and advantages of the invention are apparent from thedetailed specification, and thus, it is intended by the appended claimsto cover all such features and advantages of the invention which fallwithin the true spirit and scope of the invention. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the invention to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the invention.

1. A pedal assembly, comprising: a mounting bracket; and a pedal armpivotably connected to said mounting bracket via a pivot shaft; whereinsaid mounting bracket further comprises integrally formed bearingsurfaces to support said pivot shaft.
 2. The pedal assembly of claim 1,wherein said pivot shaft comprises a self-lubricating shaft.
 3. Thepedal assembly of claim 1, wherein said pivot shaft comprises acomposite pivot shaft.
 4. The pedal assembly of claim 1, wherein saidmounting bracket comprises a unitary component.
 5. The pedal assembly ofclaim 1, wherein said bearing surfaces comprise inwardly-protrudingsurfaces on said mounting bracket.
 6. The pedal assembly of claim 1,further comprising a treadle attached to an end of said pedal arm.
 7. Amethod of manufacturing a pedal assembly, comprising: providing amounting bracket having integrally formed bearing surfaces; providing apedal arm; and pivotably connecting the pedal arm to the mountingbracket via a pivot shaft.
 8. A pedal assembly, comprising: means forconverting translational motion to rotational motion; mounting meanshaving integrated bearing means for supporting said motion convertingmeans; and connecting means for pivotably attaching said motionconverting means and said mounting means.
 9. A pivot shaft, comprising:one or more magnetic component locating features; and one or moremagnetic component retention features; wherein at least one of saidmagnetic component locating features and said magnetic componentretention features are integrally formed on a magnetic componentmounting cap located at an end of said pivot shaft.
 10. The pivot shaftof claim 9, wherein said magnetic component locating features comprise ashield locating feature and a magnet locating feature.
 11. The pivotshaft of claim 10, wherein said shield locating feature comprises a pairof shield locating towers projecting from said magnetic componentmounting cap.
 12. The pivot shaft of claim 10, wherein said magnetlocating feature comprises a magnet locating slot in said magneticcomponent mounting cap.
 13. The pivot shaft of claim 9, wherein saidmagnetic component retention features comprise at least one pinprojecting from said magnetic component mounting cap.
 14. The pivotshaft of claim 13, wherein said at least one pin is heat-staked toretain one or more magnetic components on said magnetic componentmounting cap.
 15. The pivot shaft of claim 9, wherein said magneticcomponent mounting cap is integrally formed at said end of said pivotshaft.
 16. The pivot shaft of claim 9, wherein said shaft isself-lubricating.
 17. A method of mounting magnetic components in adynamic system, the method comprising: providing a shaft includingintegrally formed magnetic component mounting features at one endthereof; placing one or more magnetic components on the shaft; andsecuring the one or more magnetic components to the shaft.
 18. Themethod of claim 17, wherein placing one or more magnetic componentscomprises: placing a shield with reference to a shield locating feature;and placing a magnet with reference to a magnet locating feature. 19.The method of claim 17, wherein securing the magnetic componentscomprises heat-staking the magnetic components to the shaft.
 20. A pivotassembly, comprising: pivoting means including magnetic componentmounting means affixed to at least one end thereof; and magnetic meansmounted to said pivoting means.